ARM: keystone2: Allow to build with all image formats

u-boot.bin is a copy of:
u-boot-fit-dtb.bin if CONFIG_FIT_EMBED is enabled,
u-boot-dtb.bin if CONFIG_OF_SEPARATE is enabled,
u-boot-nodtb.bin if DT is not enabled.
So, use u-boot.bin to to generate keystone images instead of
u-boot-dtb.bin

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/mach-keystone/config.mk

@@ -22,13 +22,13 @@ spl/u-boot-spl.gph: spl/u-boot-spl.bin FORCE
 
 OBJCOPYFLAGS_u-boot-spi.gph = -I binary -O binary --pad-to=$(CONFIG_SPL_PAD_TO) \
 			  --gap-fill=0
-u-boot-spi.gph: spl/u-boot-spl.gph u-boot-dtb.img FORCE
+u-boot-spi.gph: spl/u-boot-spl.gph u-boot.img FORCE
 	$(call if_changed,pad_cat)
 
 ifndef CONFIG_SPL_BUILD
 MKIMAGEFLAGS_MLO = -A $(ARCH) -T gpimage -C none \
 	-a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE) -n U-Boot
-MLO: u-boot-dtb.bin FORCE
+MLO: u-boot.bin FORCE
 	$(call if_changed,mkimage)
 	@dd if=/dev/zero bs=8 count=1 2>/dev/null >> $@
 endif